A generator typically includes a rotor that is positioned within a stator such that electrical power is generated through magnetic induction as the rotor rotates within the stator. In a typical large generator such as is used in a power generation plant, the rotor has a substantially cylindrical body and a shaft that extends generally coaxially through the body so as to couple the rotor body to a prime mover such as a steam or gas turbine engine. Axially-extending rotor slots are arranged about the circumference of the rotor body extending radially inward toward a center of the shaft, and rotor conductors are positioned within the rotor slots extending axially the length of the rotor slots. The rotor conductors include end windings, sometimes referred to as end turns, positioned beyond the axial ends of the rotor slots that turn the rotor conductors such that they pass back through a different rotor slot elsewhere in the rotor body forming a plurality of rotor coils wrapped about a corresponding plurality of rotor poles formed in the rotor body.
Conventionally, the rotor conductors are formed of stiff, flat, coiled copper bars, which are also commonly referred to as rotor straps. A single rotor winding is formed by connecting the individual rotor coils in series from the beginning of the first pole to the end of the last pole. Because the rotor straps are made of stiff copper, it is conventional to connect the coil ends of adjacent poles with conductive jumpers, which are commonly known as rotor pole crossovers.
During operation of the generator, large centrifugal forces are exerted on the rotor windings and the rotor pole crossovers. Further, because the generator may be frequently started up and shut down to accommodate power generation demands, the crossovers undergo stressful mechanical and thermal cyclic duty.